Spreading on solids

If the liquid resting on a solid is volatile, it can distribute itself along the surface of the solid through the vapour thus Hardy6 found that only those acids and alcohols which have a sensible vapour pressure distribute themselves along the surface, from a drop in one spot, so as to lubricate it in any reasonable time. It does not appear to be necessary, for this kind of spreading to occur to some extent, that the contact angle should be zero it was found that the coefficient of friction of paraffin wax was 

Alty and Clark8 studied the creep of mercury up cylinders of tin, a process easily visible on account of the amalgamating action of the mercury. There was certainly a surface diffusion, much more rapid than any volume diffusion for polished surfaces the rate of travel of the mercury was of the order a few millimetres a minute, and was not much less if the exposed surface of the tin was in a bath of mineral oil, instead of in air, so that no distribution of the mercury by evaporation and condensation on other parts of the surface was possible. 

The rate of travel up the surface of the cylinder depended on the state of the surface, being much slower up a cylinder with the surface as left by turning, than on a ground or polished surface. The authors ascribe the difference to roughness actually lengthening the path but it would appear possible that the rate of diffusion is intrinsically more rapid on a surface which has been worked or polished, and therefore has a Beilby layer. The course of the worked portion of the surface, up the turned cylinder, would be a helix with a very slow rate of ascent, i.e. a very long path. 

Volmer and Adhikari5 found that needle-shaped crystals deposited from liquid or from solutions are apt to grow beyond the boundary of the liquid, without any film of liquid being perceptible on the surface it was concluded that the molecules moved along the surface of the solid crystal immediately after deposition. The proof of the absence of a liquid film on the surface does not, however, appear quite complete. 

7 Tram. Am. Electrochem. Soc., 55, 153 (1929) Tram. Faraday Soc., 28, 148 (1932) Phil. Mag., 29, 129 (1940). Benjamin and Jenkins, however, contradict this, though they find a migration of thorium over tungsten (Phil. Mag., 26,1049 (1938)). 

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We will develop an analytical formulation of the statement in Equation (8.2). This will be done for surface flame spread on solids, but it can be used more generally [1], As with the ignition of solids, it will be useful to consider the limiting cases of thermally thin and thermally thick solids. In practice, these solutions will be adequate for first-order approximations. However, the model will not consider any effects due to... 

Solution of condensed-phase heat transfer equation is needed to analyze structural response to fires and simulate flame spread on solid surfaces. The solution of this conjugate heat transfer problem simulate is typical for fires, but rarely found in commercial CFD packages. Over the years, different techniques have been developed to tackle this problem. Since solid-phase heat transfer... 

Our own investigations have concerned (a) liquid spreading on solids and the laws relating the equilibrium contact angle and the critical surface tension of wetting to solid and liquid constitution (26, 27, 28, 53, 54,62), (b) liquid/liquid displacement from solid surfaces (1,5), (c) the properties of adsorbed monolayers on solids and their relation to the monolayer retraction method (28, 54, 62), (d) the surface electrostatic potentials of adsorbed organic monolayers on metals (9, 10, 11, 58, 59), (e) the effects of surface constitution on adhesion and abhesion (60),... 

Equation 4 tells us that if 9 = 0—that is, if liquid L 2 spreads on solid Si—the maximum reversible work of adhesion is always in excess of the work of cohesion by an amount at least - Sivj) >... 

Kalliadasis S, Chang H-C (1996) Dynamics of liquid spreading on solid surfaces, bid Eng Chem Res 35 2860-2874... 

Kalliadasis S, Chang H-C (1996) Dynamics of Uquid spreading on solid surfaces. Ind Eng Chemistry Res 35 2860-2874 Ausserr D, Picard AM, Leger L (1986) Existence and role of the precursor film in the spreading of polymer Uquids. Phys Rev Lett 57 2671-2674... 

Ngan C, Dussan E. (1989) On the dynamics of liquid spreading on solid-surfaces./T/KtW Mech 299-. 191-226. 

As illustrated in Fig. 18a, oily materials, of which the surface tension seldom exceeds 25 mN/m, spread on solid surfaces of higher surface tension (surface free energy), like... 

Problem 4.8 Adhesion and spreading on solid-liquid interfaces... 

Rosenblat, S. Davis, S.H. How do liquid drops spread on solids. In Frontiers of Fluid Mechanics Davis, S.H. Lumley, J.L., Eds. Springer-Verlag Berlin, 1985 171-183. 

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